Thrombocytopenia and immune thrombocytopenia: Viva

This is the classic presentation of newly diagnosed immune thrombocytopenia in a well preschool child. The structured oral runs from the diagnostic criteria through the observation decision, the first-line therapy if the bleeding worsened, the second-line strategy, and the trial evidence. ^[1][4]

Opening: make the diagnosis

Examiner. The platelet count is 12 times ten to the nine per litre. What is the diagnosis, and how do you confirm it? ^[4]

Candidate. This is immune thrombocytopenia, ITP, defined by the Rodeghiero standard as an isolated thrombocytopenia with a platelet count under 100 times ten to the nine per litre, in an otherwise well child, with a normal blood film showing large platelets and no blasts, and no hepatosplenomegaly or lymphadenopathy. The diagnosis is clinical and is made by exclusion. The normal haemoglobin and white cell count, the large platelets and the absence of blasts on the film, the well child, and the absence of organomegaly all fit. A bone marrow aspirate is not indicated, because the ASH 2019 guideline recommends against the routine marrow aspirate in the typical presentation. ^[1][4]

Examiner (probe). What would make you doubt the diagnosis? ^[3]

Candidate. The features that exclude ITP are the other cytopenias, the anaemia or the neutropenia, the blast cells on the film, the hepatosplenomegaly or the significant lymphadenopathy, and the fever or the bone pain. Any of these points to the acute leukaemia or another infiltrative disorder, and I would order the bone marrow aspirate. The small platelets would point to the Wiskott-Aldrich syndrome, and the schistocytes would point to the haemolytic uraemic syndrome. ^[3]